Protective window for optical sight

ABSTRACT

The invention comprises a protective window for an optical sight. In accordance with one embodiment of the invention, an optical sight ( 20 ) may comprise an optical component ( 182, 300 ) transmitting an image of a scene. A protective window ( 180, 430 ) may be disposed approximate to an internal side of the optical component ( 180, 300 ) to obstruct dirt from contacting the internal side of the optical component.

RELATED APPLICATIONS

This application is related to copending U.S. patent. application Ser.No. 08/741,289, entitled “ALIGNMENT ELEMENT FOR MULTIPLE CHANNEL SIGHTAND METHOD”; copending U.S. patent application Ser. No. 08,741,614,entitled “RETICLE ASSEMBLY FOR OPTICAL SIGHT”; copending U.S. Patentapplication Ser. No. 08/741,883, entitled “CHANNEL SELECTOR FOR MULTIPLECHANNEL SIGHT”; copending U.S. patent application Ser. No. 08/741,481,entitled “MOUNTING ASSEMBLY FOR OPTICAL SIGHT”; copending U.S. patentapplication Ser. No. 08/741,920, entitled MOUNTING ASSEMBLY FOR IMAGEINTENSIFIER TUBE IN OPTICAL SIGHT”.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to optical sights, and moreparticularly to a protective window for an optical sight.

BACKGROUND OF THE INVENTION

Day/night sights would typically be used by military and law enforcementpersonnel to aim weapons used in both day time and night timeconditions. Typically, a day/night sight includes an objective lens, areticle and an eyepiece in series with parallel day and night channels.A channel selector may be used to alternatively direct an image of atarget into the day or night channel.

In a day/night sight, the objective lens and the eyepiece may betelescopic to provide a magnified image of the target. The day channelgenerally uses ambient light to generate an image of the target. Theimage may be projected to the reticle during day time use to be viewedby the user. The night channel generally includes an image intensifierto generate an illuminated image of the target. The illuminated imagemay be transmitted to the reticle during night time use to be viewed bythe user. The reticle may include markings for aiming the weapon.

A problem with day/night and other types of sights is dust enclosedwithin the sight. The dust may interfere with the user's view of ascene. This is especially true of telescopic sights that may magnify thedust.

SUMMARY OF THE INVENTION

Accordingly, a need has arisen in the art for an improved optical sight.The present invention provides a protective window that substantiallyeliminates or reduces the disadvantages and problems associated withprior optical sights.

In accordance with the present invention, a sight may comprise anoptical component to transmit an image of a scene. A protective windowmay be disposed proximate to an internal side of the optical component.The protective window may be sealed to the internal side of the opticalcomponent to obstruct dirt from contacting the internal side of theoptical component.

In one embodiment of the invention, an image intensifier tube maycomprise a projecting end to project an intensified image of a scene. Aprotective window may be disposed between the projecting end of theimage intensifier tube and an image plane. The protective window may besealed to the projecting end to obstruct dirt from contacting theprojecting end.

In another embodiment of the invention, a reticle assembly may include aprotective window for a reticle. The protective window may be disposedbetween the reticle and a scene. The protective window may be sealed tothe reticle to obstruct dirt from contacting the reticle.

Important technical advantages of the present invention includeproviding an improved sight. In particular, dirt enclosed within thesight is collected at a plane that is out of focus with a viewing or animage plane. Accordingly, the image of the scene may be viewed andmagnified with little or no interference from dirt in the sight.

Still another important technical advantage of the present inventionincludes providing an improved image intensifier tube. In particular, aprotective window may be sealed to a projecting end of the imageintensifier tube. The protective window may collect dirt at a plane thatis out of focus with the projecting end. Accordingly, the projecting endmay be viewed and magnified with little or no interference from dirtthat has settled within the sight.

Yet another important technical advantage of the present inventionincludes providing an improved reticle assembly. In particular, aprotective window may be sealed to a reticle. The protective window maycollect dirt at a plane that is out of focus with the reticle.Accordingly, the reticle may be viewed and magnified with little or nointerference from dirt in the sight.

Other technical advantages will be readily apparent to one skilled inthe art from the following figures, descriptions, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side view of a telescopic day/night sight mounted to Aweapon in accordance with one embodiment of the present invention;

FIG. 2 is a schematic drawing of the optical components of the sight ofthe FIG. 1;

FIG. 3 is a perspective view of a mirror assembly for selectivelydirecting light into the day or night channel of the sight of FIG. 1;

FIG. 4 is a cross sectional view of the mirror pivot assembly of FIG. 3;

FIG. 5 is a exploded view of a mounting system for an image intensifiertube of the night channel of the sight of FIG. 1;

FIG. 6 is a cross sectional view of the mounting system for the imageintensifier tube of FIG. 5.

FIG. 7 is a perspective view with portions broken away of a housing forsecuring lenses of the sight of FIG. 1;

FIG. 8 is a cross sectional view of a clamping assembly for securinglenses housing of FIG. 7;

FIG. 9 is a perspective view of a mirror assembly for selectivelydirecting the image of the day or night channel to a reticle assembly ofthe sight of FIG. 1;

FIG. 10 is a cross sectional view of the mirror assembly of FIG. 9;

FIG. 11 is an exploded view of the reticle assembly of the sight of FIG.1;

FIG. 12 is a top plan view with portions broken away of the reticleassembly of FIG. 11;

FIG. 13 is a top plan view of an alignment element of the sight of FIG.1;

FIG. 14 is a perspective view of a pair of prisms of the alignmentelement of FIG. 13;

FIG. 15 is a cross sectional view of the alignment element of FIG. 13;and

FIG. 16 is an exploded view of a mounting assembly of the sight of FIG.1.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiments of the present invention and its advantagesare best understood by referring now in more detail to FIGS. 1-16 of thedrawings, in which like numerals refer to like parts throughout theseveral views. FIG. 1 shows a perspective view of a multiple channelsight 20 for aiming a weapon 22. The multiple channel sight 20 may beused by persons such as law enforcement and military personnel to aimthe weapon 22 in disparate conditions. The weapon 22 may be a rifle orany other type of weapon system that fires an aimed projectile or aimedbeam such as a laser. The multiple channel sight 20 may also be used forsurveillance when not mounted on the weapon 22.

In one embodiment, the multiple channel sight 20 may be a day/nightsight that can be operated in day and night conditions. As shown by FIG.1, the day/night sight 20 may include an objective lens assembly 24 at aforward end 26, a body section 28 covered by a housing 30 and an eyepiece 32 at a rearward end 34. As used herein, the term “forward”designates a direction toward an object to be observed and the term“rearward” designates a direction toward a user of the day/night sight20.

Controls 36 for operating the day/night sight 20 may be disposed on anexterior 38 of the housing 30. Preferably, the controls 36 are locatedat the top of the housing 30 so that they may be reached and manipulatedwith either hand of the user. Individual controls may have uniqueidentifying embossments that allow the user to readily distinguishbetween the controls 36 in the dark by feel.

A channel selector switch 39 may also be disposed on the exterior 38 ofthe housing 30. As described in detail below, the channel selectorswitch 39 may operate a channel selector to direct an image of a scenethrough one of the channels of the sight 20.

An azimuth adjusting screw 40 and an elevation adjusting screw 42 forbore sighting corrections may also be provided on the exterior 38 of thehousing 30. The azimuth adjusting screw 40 allows bore sighting to beadjusted for wind speed and direction. The elevation adjusting screw 42allows bore sighting to be adjusted for gravitational effects.

A protective eye guard 44 may be provided at the rearward end 34 of thesight 20. The protective eye guard 44 may be shaped to fit around theuser's eye to prevent ambient light from interfering with the user'sview of the image generated by the sight. The protective eye guard 44also prevents light generated by the sight 20 from being visible outsidethe sight 20.

FIG. 2 illustrates optical components for one embodiment of theday/night sight 20. The objective lens assembly 24 may collect an imageof a scene. The image collected by the objective lens assembly 24 may bedirected into a night channel 54 or a day channel 56. As described indetail below, the night channel 54 may electronically intensify theimage of the scene. The intensified image may be projected onto a commonreticle assembly 58. There, the image may be viewed by the user throughan eyepiece 60. As also described in detail below, the day channel 56may relay the image of the scene onto the reticle assembly 58. There,the user may view the image through the eyepiece 60.

The day/night sight 20 may include a channel selector to alternativelydirect the image of the scene into the night channel 54 or the daychannel 56. In one embodiment, the channel selector may include a firstmirror assembly 64 and a second mirror assembly 66. In this example, thefirst mirror assembly 64 may be disposed between the objective lensassembly 24 and entrances of the night and day channels. The secondmirror assembly 66 may be disposed between exits of the night and daychannels and the reticle assembly 58.

An optical bench (not shown in FIG. 2) may be provided for mounting theoptical components in the sight 20. The optical bench may be one or moreframes or other internal structures to which components may by mounted.The optical bench may include predefined pathways, recesses, andopenings for securing the optical components in a proper spatialrelation. It will be understood that the design of the optical benchwill vary with the configuration and the optical components of the sight20.

In FIG. 2, the night channel 54 is located above the day channel 56 whenthe sight 20 is in an upright position. It should be understood that thesight 20 may be configured with the day channel 56 positioned above thenight channel 54. Additionally, the day channel 56 may be positionedalong side the night channel 54.

The objective lens assembly 24 of the sight 20 may be a variable zoomassembly or a single field of view assembly. For a variable zoomembodiment, the objective lens assembly 24 may include a plurality oflenses positioned along an optical axis 75. In accordance withconventional practice, the radius of curvature of a lens will be definedas positive if the center of curvature lies rearward of the lens andwill be defined as negative if the center of curvature lies forward ofthe lens along the optical axis. A lens will be defined as converging ifthe lens focusing power causes parallel light rays to converge and willbe defined as diverging if the lens focusing power causes parallel lightrays to appear to originate from a virtual focus.

For the embodiment of FIG. 2, the objective lens assembly 24 may includean objective lens 80 followed by a positive converging lens 82, a pairof negative diverging lenses 84, a positive diverging lens 86 and afocusing lens 88. It should be understood that additional or disparatelenses may be used within the sight 20 in accordance with the presentinvention.

From the objective lens assembly 24, the image of the scene passes alongthe optical axis 75 to the first mirror assembly 64. As described inmore detail below, the first mirror assembly 64 may include a swingableor flip-flop mirror 100 rotatable between a night position 102 and a dayposition 104. In the night position 102, the mirror 100 does notintercept the optical axis 75. Accordingly, the image of the scenepasses through the first mirror assembly 64 into the night channel 54.

In the day position 104, the mirror 100 intercepts the optical axis 75to deflect the image of the scene into the day channel 56. In oneembodiment, the entrance of the day channel 56 is normal to the opticalaxis 75. In this embodiment, the mirror 100 may intercept the opticalaxis 75 at a forty-five (45) degree angle to direct the image into theentrance of the day channel 56.

FIGS. 3-4 illustrate one embodiment of the first mirror assembly 64. Asshown by FIG. 3, the first mirror assembly 64 may comprise an annularframe 110 having a central aperture 112. The frame 110 may be secured tothe optical bench (not shown in FIG. 3) with the central aperture 112disposed along the optical axis 75. The central aperture 112 allows theimage of the scene to pass through the frame 110 when the mirror 100 isin the night position 102 (FIG. 2).

A support 114 for mounting the mirror 100 may be rotatably coupled tothe frame 110 in the central aperture 112. The support 114 may rotateabout an axis 116 normal to the optical axis 75. The mirror 100 may bemounted to the support 114 for rotation about the axis 116. Accordingly,the mirror 100 may swing or flip-flop between the night position 102(FIG. 2) and the day position 104 (FIG. 2).

An arm 117 may be coupled to the support 114 for rotating the firstmirror assembly 64 between the night position 102 and the day position104. The arm 117 may be mechanically or electrically coupled to thechannel selector switch 39. The channel selector switch 39 may rotatethe first and second mirror assemblies 64 and 66 together to theirrespective night and day positions.

A pivot shaft 118 may be fixably coupled to the support 114 to providethe axis 116 of rotation. The pivot shaft 118 may be a thin metal rod.The pivot shaft 118 may include opposed ends 120 extending from thesupport 114 for connection with the frame 110.

As show by FIG. 4, the frame 110 may include a trough 122 to receiveeach of the opposed ends 120. The troughs 122 may extend in alignmentwith one another on opposite sides of the aperture 112. In oneembodiment, the troughs 122 may be formed in the frame 110. In thisembodiment, the troughs 122 may be formed by a router or similar toolcapable of forming the troughs 122 along a straight line. The troughs122 may have substantially parallel sidewalls 124 and a furrowed bottom126. It will be understood that the troughs 122 may be of other shapesand configurations capable of receiving the opposed ends 120.

Each end 120 of the pivot shaft 118 may be disposed in one of thetroughs 122. A plate 128 may be coupled to the frame 110 across eachtrough 122 to secure the ends 120 of the pivot shaft 118 in the troughs122. The frame 110 may include a cavity 130 across each trough 122 toreceive the plates 128. The cavities 130 may be sized to receive theplates 128 such that a top 132 of the plates 128 is flush with a surface134 of the frame 110.

In accordance with one aspect of the present invention, the plates 128may contact the ends 120 of the pivot shaft 118 to control a shiftingtorque of the mirror 100 relative to the frame 110. The shifting torqueis the torque necessary to shift the mirror 100 between the nightposition 102 and the day position 104. The desired shifting torque maybe a balance between allowing the mirror 100 to smoothly move betweenthe night and day positions and preventing the mirror 100 fromaccidentally moving between the night and day positions.

In one embodiment, the ends 120 of the pivot shaft 118 may extend abovethe troughs 122 for contact with the plates 128. It will be understoodthat the ends 120 of the pivot shaft 118 and the plates 128 mayotherwise contact one another within the scope of the present invention.For example, a portion of the plates 128 may extend into the troughs 122for contact with the ends 120 of the pivot shaft 118. In such anembodiment, the portion of the plates 128 extending into the troughs 122may be a non integral insert (not shown).

The shifting torque of the mirror 100 may be controlled by regulatingthe friction caused by the contact between the plates 128 and the ends120 of the pivot shaft 118. In one embodiment, the plates 128 may eachbe adjustably coupled to the frame 110 by a pair of screws 136. In thisembodiment, friction caused by contact between the plates 128 and theends 120 of the pivot shaft 118 may by regulated by tightening orloosing the screws 136. It will be understood that the plates 128 may beotherwise adjustably coupled to the frame 110 within the scope of thepresent invention.

Returning to FIG. 2, with the mirror 100 in the night position 102, theimage of the scene passes from the objective lens assembly 24 throughthe first mirror assembly 64 into the night channel 54. In the nightchannel 54, the image may be received by an image intensifier tube 150disposed along the optical axis 75. The image intensifier tube 150 mayconvert the image of the scene into an electron pattern. The imageintensifier tube 150 may be inverting or non-inverting. The electronsmay be multiplied and transmitted onto a phosphor screen. The phosphorscreen may generate an intensified image corresponding to the image ofthe scene. The intensified image may be projected to the reticleassembly 58 where it can be viewed by the user through the eye piece 60.

In accordance with one aspect of the present invention, the imageintensifier tube 150 may be mounted to the optical bench for selectiverotation. Rotation of the image intensifier tube 150 rotates any offsetof the intensified image generated by the image intensifier tube 150. Anoffset of the intensified image may be caused by an offset between themechanical and optical axis of the image intensifier tube 150.Accordingly, the image intensifier tube 150 may be rotated until anyoffset of the intensified image at the reticle assembly 58 lies along adirection from which the intensified image can be adjusted to center. Asdescribed in more detail below, the offset of the intensified image maybe centered along a direction of the reticle assembly 58 by adjustingthe second mirror assembly 66. In one embodiment, the second mirrorassembly 66 may center the offset of the intensified image along avertical direction of the reticle assembly 58. It will be understoodthat the second mirror assembly 66 may be configured to instead centerthe intensified image along another direction of the reticle assembly58.

FIGS. 5-6 illustrate one embodiment of a mounting assembly 152 forrotatably mounting the image intensifier tube 150 to the optical bench(not shown in FIG. 5). As shown by FIG. 5, the mounting assembly 152 maycomprise an annular housing 154 having a central aperture 156 to receivethe image intensifier tube 150. In one embodiment, the housing 154 maybe fixably secured at a forward end 155 to the optical bench with thecentral aperture 156 disposed along the optical axis 75. In thisembodiment, the housing 154 may be secured to the optical bench by apair of screws (not shown) each threaded through a tab 157 of thehousing 154 into the optical bench.

A retainer 158 for engaging the image intensifier tube 150 may berotatably coupled to the housing 154. It will be understood that thehousing 154 and retainer 158 may be otherwise coupled to one another andto the optical bench so long as the image intensifier tube 150 isselectably rotatable relative to the optical bench. For example, thehousing 154 may be rotatably coupled to the optical bench and theretainer 158 fixably coupled to the housing 154.

In one embodiment, the retainer 158 may be rotatably coupled proximateto a rearward end 159 of the housing 154. In this embodiment, theretainer 158 may comprise a rounded slide 160. The rounded slide 160 mayhave a circumference slightly smaller than that of the central aperture156 in order to fit easily, but not loosely, and to be rotatable withinthe central aperture 156. It will be understood that the retainer 158may be otherwise coupled to the housing 154 within the scope of theinvention.

As shown by FIG. 6, the slide 160 may include a socket 166 sized tofrictionally receive the image intensifier tube 150. The socket 166 mayhave an aperture 167 through which the intensified image may beprojected. An alignment pin 168 may extend from the socket 166 forengagement with a mating hole (not shown) of the image intensifier tube150. The alignment pin 168 may index an opening 170 of the slide 160with electrical contacts 172 of the image intensifier tube 150.Accordingly, the slide 160 will only engage the image intensifier tube150 when the opening 170 is aligned with the electrical contacts 172.The alignment pin 168 may also insure that the image intensifier tube150 rotates with the slide 160.

An insert 174 may be fitted into the opening 170 to secure theelectrical contacts 172 in proper relation to one another for engagementwith a plug (not shown). The plug may provide power and control for theimage intensifier tube 150. The plug may be secured along a rearwardside of the slide 160 by a strain relief member 176. The strain reliefmember 176 prevents the plug from interfering with projection of theintensified image. It will be understood that the plug may be otherwisesecured within the scope of the invention.

A locking device 177 may selectively secure the image intensifier tube150 relative to the optical bench. In one embodiment, the locking device177 may be a locking ring 178. The locking ring 178 may have a threadedexterior adapted to engage a threaded section 179 of the housing 154.The locking ring 178 may be tightened against the slide 160 to fixablysecure the image intensifier tube 150 between the slide 160 and theoptical bench. Conversely, the locking ring 178 may be loosened againstthe slide 160 to allow the image intensifier tube 150 to be rotatedbetween the slide 160 and the optical bench.

Accordingly, the slide 160 may be rotated about the optical axis 75 torotate the image intensifier tube 150 until any offset of theintensified image is vertically in line with the center of the reticleassembly. The locking ring 178 may then be tightened against the slide160 to secure the image intensifier tube 150 relative to the opticalbench. As previously described, the second mirror assembly 66 may thenbe adjusted to vertically center the intensified image at the reticleassembly 58.

In accordance with one aspect of the present invention, a protectivewindow 180 may be sealed to a projection end 182 of the imageintensifier tube 150. The projection end 182 projects the intensifiedimage to the reticle assembly 58. The protective window 180 may shieldthe projection end 182 from dirt that has settled within the sight 20.As used herein, the term “dirt” means soiling substances such as dust,oils, and the like that are capable of interfering with the user's viewof the image.

As shown in FIG. 6, the protective window 180 may be sealed directly tothe projecting end 182 of the image intensifier tube 150. The projectingend 182 may be a phosphorous screen. The protective window 180 may besealed to the projecting end 182, a shoulder spaced apart from theprojecting end 182, a spacer ring, or the like. The protective window180 may be sealed with a known adhesive for optical surfaces or thelike.

The protective window 180 shields the projection end 182 of the imageintensifier tube 150 by collecting dirt at a plane 184 that is out offocus with the projection end 182. Accordingly, the intensified imagemay be viewed and magnified with little or no interference from dirtthat has settled within the sight 20. The distance between theprojection end 182 and the collecting plane 184 may be varied byadjusting the thickness of the protective window 180 or of a spacerring.

From the image intensifier tube 150, the intensified image may bepropagated through the night channel 54 by one or more opticalcomponents. For the embodiment shown by FIG. 2, the night channel mayinclude a first lens set 200 disposed along the optical axis 75 and asecond lens set 202 disposed along a second optical axis 205 normal tothe optical axis 75. A ninety degree prism 206 may direct an image beamfrom the optical axis 75 to the second optical axis 205.

The first lens set 200 may include a negative converging lens 210, apositive diverging lens 212 and a positive converging lens 214. Thesecond lens set 202 may include a positive diverging lens 216 and apositive converging lens 218. It should be understood that additional ordisparate lenses may be used with the first and second lens sets 200 and202.

In accordance with one aspect of the present invention, the lenses maybe clamped in a direction perpendicular to their optical axis.Perpendicular clamping prevents the lenses from moving along the opticalaxis during the clamping process. Such movement along the optical axismay distort the image of the scene at the reticle assembly 58.

FIG. 7 illustrates one embodiment of a lens assembly 220 for housinglenses of the first lens set 200. As shown by FIG. 7, the lens assembly220 may include an annular housing 222 having a central aperture 224.The central aperture 224 allows the image of the scene to pass throughthe housing 222 and be acted upon by the lenses. The housing 222 may besecured to the optical bench with the central aperture 224 disposedalong the optical axis 75.

For the first lens set 200, a spacer 226 may be placed between the lens210 and the lens 212 to position the lenses 210 and 212 at a desireddistance from one another. Lens 214 may be positioned directly next tolens 212. The lenses 210, 212 and 214 and the spacer 226 may be securedin the housing 222 with a known adhesive or the like. It will beunderstood that other methods may be used to secure the lenses andspacer in the housing 220. For example, the lenses and spacer may besecured in the housing 222 by retainers, locking rings, detents and thelike capable of clamping the lenses and spacer together between ends ofthe housing 222.

FIG. 8 illustrates one embodiment of a clamping assembly 230 forclamping the lens assembly 220 in a direction perpendicular to theoptical axis 75. As shown by FIG. 8, the clamping assembly 230 mayinclude a clamp 232 having a surface 234 adapted to engage a periphery236 of the lens assembly 220. The clamp 232 may be tightened to securethe lens assembly 220 between the clamp 232 and a stop 238.

In one embodiment, the clamp 232 may comprise a brace 240 and a screw242. The brace 240 may include the surface 234 adapted to engage theperiphery 236 of the lens assembly 220. The periphery 236 of the lensassembly 220 may be the annular housing 222. In this case, the surface234 may have a concave shape adapted to engage the annular housing 222.

The screw 242 may engage a threaded section 244 of the optical bench andcontact the brace 240 opposite the surface 234. The stop 238 may be asection of the optical bench opposite the screw 242. The screw 240 maybe adjustable in the direction of the stop 238 to secure the lensassembly 220 within the optical bench.

It will be understood that lenses 216 and 218 of the second lens set 202may be secured in a lens assembly as described above in connection withFIG. 7. It will be further understood that the lens assembly of thesecond lens set 202 may be clamped in the direction perpendicular to thesecond optical axis 205 as described above in connection with FIG. 8.

Referring back to FIG. 2, the intensified image may pass from the nightchannel 54 to the second mirror assembly 66. As described in more detailbelow, the second mirror assembly 66 may include a swingable orflip-flop mirror 250 rotatable between a night position 252 and a dayposition 254. In the night position 252, the mirror 250 may interceptthe second optical axis 205 of the night channel 54 to direct theintensified image to the reticle assembly 58. The reticle assembly 58may be disposed along a third optical axis 255. In one embodiment, thethird optical axis 255 may be normal to the second optical axis 205. Inthis embodiment, the mirror 250 may intercept the second optical axis205 at a forty-five (45) degree angle to direct the intensified image tothe third optical axis 255. In the day position 254, the mirror 250 doesnot intercept a third optical axis 255. Accordingly, an image of the daychannel 56 may pass through the second mirror assembly 66 to the reticleassembly 58.

FIGS. 9-10 illustrate one embodiment of the second mirror assembly 66.As shown by FIG. 9, the second mirror assembly 66 may include a support260 rotatably coupled to the optical bench. The support 260 may rotateabout an axis 262 normal to the third optical axis 255. The mirror 250may be mounted to the support 260 for rotation about the axis 262.Accordingly, the mirror 250 may swing or flip-flop between the nightposition 252 (FIG. 2) and the day position 254 (FIG. 2).

An arm 263 may be coupled to the support 260 for rotating the secondmirror assembly 66 between the night position 252 and the day position254. The arm 263 may be mechanically or electrically coupled to thechannel selector switch 39. As previously described, the channelselector switch 39 may rotate the first and second mirror assemblies 64and 66 together to their respective night and day positions.

As best shown by FIG. 10, a pivot assembly 264 may be fixably coupled tothe support 260 to provide the axis of rotation 262. In one embodiment,the pivot assembly 264 may comprise a first insert 266 and a secondinsert 268. The first and second inserts 266 and 268 may be press fitinto opposite edges 270 of the support 260. The first and second inserts266 and 268 may have opposed recess ends 272 in alignment with oneanother. The outer edge of the recess ends 272 may be substantiallyflush with the edges 270 of the support 260.

A ball 274 may engage each of the recessed ends 272. In one embodiment,the balls 274 may be sized to sit in the recessed ends 272. In thisembodiment, the recessed ends 272 may be cone-shaped. It will beunderstood that the recessed ends 272 may have a different shape orconfiguration so long as the ends are capable of engaging the balls 274.

A holder assembly 276 may engage each of the balls 274. In oneembodiment, each holder assembly 276 may include a recessed end 278 toengage one of the balls 274. As with the recessed ends 272 of theinserts 266 and 268, the recessed ends 278 of the holder assemblies 276may be cone-shaped. It will be understood that the recessed ends 278 ofthe holder assemblies 276 may have a different shape or configuration solong as the ends are capable of engaging the balls 274.

In accordance with one aspect of the present invention, the holderassemblies 276 may be adjustable along the axis 262 of rotation of thesupport to control a shifting torque of the mirror 250 relative to theoptical bench. A shifting torque is a torque necessary to shift themirror 250 between the night position 252 and the day position 254. Thedesired shifting torque may be a balance between allowing the mirror 250to smoothly move between the day and night positions and preventing themirror 250 from accidentally moving between the day and night positions.

In one embodiment, the holder assemblies 276 may each comprise a bushing280 and an adjustment screw 282. The recessed end 278 for engaging theball 274 may be disposed at an end of the adjustment screw 282. Thebushing 280 may be mounted in the optical bench along the axis ofrotation 262 of the support 260. The adjustment screw 282 may engage thebushing 280 along the axis of rotation 262.

Each of the adjustment screws 282 may be threaded to adjustably engagethe bushing 280. Accordingly, the adjustment screws 282 may be tightenedor loosened against the balls 274. The shifting torque of the mirror 250may be controlled by regulating the tension on the balls 274 caused bythe adjustment screws 282.

The adjustment screws 282 may each include a smooth bore section 284press fit into smooth bore cavity 286 of the bushing 280. The press fitprevents the support 260 from shifting from the axis of rotation 262 dueto play in the threads of the bushings 280 and the adjustment screws282.

Referring back to FIG. 9, the second mirror assembly 66 may include analignment screw 288 to control the angle at which the mirror 250intercepts the second optical axis 205. The alignment screw 288 maycontact the back of the support 260. The alignment screw 288 may raisethe mirror 250 to reduce the angle at which the mirror 250 interceptsthe second optical axis 205. This adjustment will vertically raise theintensified image at the reticle assembly 58. Conversely, the alignmentscrew 288 may lower the mirror 250 to increase the angle at which themirror 250 intercepts the second optical axis 205. This adjustment willvertically lower the intensified image at the reticle assembly 58.

With the mirror 250 in the night position 252, the intensified image maybe directed to the reticle assembly 58. At the reticle assembly 58, theintensified image may be projected onto a reticle 300 (FIG. 11). Asdescribed in more detail below, the reticle 300 may include a targetingpattern 301 for aligning the sight 20 with a target. The position of thetargeting pattern 301 may be adjusted in the reticle assembly 58 tocompensate for wind speed, wind direction, and gravitational effects.Typically, the necessary reticle adjustment increases with the distanceto the target.

In accordance with one aspect of the present invention, the reticleassembly 58 may allow for increased adjustment of the reticle 300. Thisincrease permits the user of the sight 20 to aim the weapon 22 at moredistant targets. Adjustment of the reticle 300 may be increased bydisposing sliding components of the reticle assembly 58 in slots withsidewalls that form the control surfaces for the sliding components.Accordingly, additional space need not be set aside in the reticleassembly 58 for installing control surfaces of the sliding components.

FIGS. 11-12 illustrate one embodiment of the reticle assembly 58. Asshown by FIG. 11, the reticle assembly 58 may comprise a substantiallyannular housing 302 with a substantially round inside surface 304 and abottom 306. The inside surface 304 may include a first side 310 and anopposed second side 312. The inside surface 304 may also include a thirdside 314 and opposed fourth side 316 between the first and seconds sides310 and 312. The bottom 306 of the housing 302 may have an extendedaperture 308. The extended aperture 308 may be substantially square inshape with rounded corners.

A pair of opposed side walls 318 may be formed at the bottom 306 of thehousing 302 along the third and fourth sides 314 and 316. The opposedside walls 318 may form a first slot 322. A pair of ways 320 may definethe opposed side walls 318. Accordingly, the first slot 322 may extendbetween the first side 310 and the second side 312 of the inside surface304.

A cross slide 330 may be disposed in the first slot 322. The cross slide330 may be substantially rectangular in shape and have an elongatedaperture 332. The elongated aperture 332 may be substantiallyrectangular in shape with rounded corners.

The cross slide 330 may have substantially parallel edges 334 slidablyengaging the ways 320 of the housing 302. The ways 320 function ascontrol surfaces for the cross slide 330. Accordingly, the cross slide330 may slide along the ways 320 between the first side 310 and thesecond side 312 of the housing 302.

The cross slide 330 may have opposed ends 336 facing the first andsecond sides 310 and 312 of the housing 302. The ends 336 may be roundedto substantially conform to the shape of the first and second sides 310and 312. This allows the cross slide 330 to slide toward the first side310 until it is substantially flush with that side and to slide towardthe second side 312 until it is substantially flush with that side.Accordingly, the cross slide 330 may slide a maximum distance within thehousing 302.

A second slot 340 may be formed in the cross slide 330. The second slot340 may be substantially normal to the first slot 322. Accordingly, thesecond slot 342 may extend between the third side 314 and the fourthside 316 of the housing 302. The second slot 340 may have an open end342, an opposite closed end 344 and opposed side walls 346. A pair ofways 348 may define the opposed side walls 346.

A reticle holder 350 may be disposed in the second slot 342 of the crossslide 330. The reticle holder 350 may include a base 352, a viewingaperture 354 and a projection 356 extending from the base 352 around theviewing aperture 354. The viewing aperture 354 may be substantiallyround in shape.

The base 352 of the reticle holder 350 may have substantially paralleledges 358 slidably engaging the ways 348 of the cross slide 330. Theways 348 function as control surfaces for the reticle holder 350.Accordingly, the reticle holder 350 may slide along the ways 348 betweenthe third side 314 and the fourth side 316 of the housing 302.

The base 352 of the reticle holder 350 may have opposed ends 360 facingthe third and fourth sides 314 and 316 of the housing 302. The ends 360may be rounded to substantially conform to the shape of the third andfourth sides 314 and 316. This allows the reticle holder 350 to slidetoward the third side 314 until it is substantially flush with that sideand to slide toward the fourth side 316 until it is substantially flushwith that side. Accordingly, the reticle holder 350 may slide a maximumdistance within the cross slide 330.

The projection 356 may include an intermediate section 362 and anenlarged head 364. The enlarged head 364 may include a top recess 366sized to receive the reticle 300. The reticle 300 may be substantiallysquare in shape with rounded corners. The reticle 300 may be secured inthe recess 366 with an optical adhesive or the like. It will beunderstood that the reticle 300 may be otherwise secured in the recess366 within the scope of the invention.

As previously discussed, the reticle 300 may include the targetingpattern 301. The targeting pattern 301 may be cross-hairs. It will beunderstood that other targeting patterns may be used that are capable ofaligning the sight 20 with the target.

A first notch 368 and a second notch 370 may be formed in the head 364.The notches 368 and 370 may extend from the reticle 300 to an exterior372 of the head 364. A reticle light 374 may be disposed in the firstnotch 368. The reticle light 374 may illuminate the targeting pattern301 during night time use. A status indicator 376 may be disposed in thesecond notch 370. In one embodiment, the status indicator 376 mayactivate to alert the user of a low battery status. The reticle light374 and the status indicator 376 may be light emitting diodes (LED).Power and control for the reticle light 374 and the status indicator 376may be provided by a flex circuit 378. The flex circuit 378 allows thereticle light 374 and the status indicator 376 to be moved with thereticle 300. The flex circuit 378 may extend from the reticle holder 350down a groove 379 of the housing 302 of the reticle assembly 58.

An annular cover 380 may clamp over the enlarged head 364 to secure thereticle light 374 and the status indicator 376 in the first and secondnotches 368 and 370. The cover 380 may include an aperture 384substantially matching the shape and size of the reticle 300. Theaperture 384 allows the reticle 300 to be viewed from the eye piece 60without interference from the cover 380.

A guide ring 390 may be disposed about the intermediate section 362 ofthe projection 356. The guide ring 390 may sit on the ways 320 of thefirst slot 322. It will be understood that the guide ring 390 may beotherwise secured in the housing 302 as long as the guide ring 390 ispositioned about the intermediate section 362.

The guide ring 390 may include a guide 392 to define an area in whichthe reticle holder 350, and thus the reticle 300, may be adjusted. Theguide 392 may be substantially square in shape with rounded corners. Thecorners may be rounded in conformance with a diameter of theintermediate section 362. Accordingly, the intermediate section 362 mayfit substantially flush against the corners of the guide 392 to maximizemovement of the intermediate section 362 in the guide 392.

The guide ring 390 may include an alignment pin 394. The alignment pin394 may engage a mating hole 396 formed in one of the ways 320 of thefirst slot 322. The alignment pin 394 may index the guide 392 with theextended aperture 308 of the housing 302, the elongated aperture 332 ofthe cross slide 330 and the viewing aperture 354 of the reticle holder350. Accordingly, as the reticle holder 350 is moved within the crossslide 330 and the cross slide 330 is moved within the housing 302, theviewing aperture 354 continually overlaps the elongated aperture 332 andthe elongated aperture 332 continually overlaps the extended aperture308. As a result, an image may be projected onto the reticle 300 nomatter the position of the reticle 300 in the reticle assembly 58.

An intermediate washer 396 may be disposed between the guide ring 390and the reticle holder 350. The intermediate washer 396 may reducefriction between the guide ring 390 and the reticle holder 350. In oneembodiment, the intermediate washer 396 may be constructed of Teflon. Itwill be understood that the intermediate washer 396 may be constructedof other materials capable of reducing friction between sliding members.

A locking ring 398 may secure the guide ring 390, intermediate washer396, reticle holder 350 and cross slide 330 in the reticle housing 302.The locking ring 398 may be threaded to engage threads 400 of thehousing 302. The locking ring 398 may be tightened to a point where thereticle holder 350 and the cross slide 330 move smoothly but not looselywithin the reticle housing 302.

As best shown by FIG. 12, a first spring element 410 may be disposedbetween an end of the cross slide 330 and the first side wall 310 of thehousing 302. The first spring element 410 may comprise a pair of springs412. The springs 412 may bias cross slide 330 away from the first side310 of the housing 302. Similarly, a second spring element 414 may bedisposed between the closed end 344 of the second slot 340 and the base352 of the reticle holder 350. The second spring element 414 maycomprise a pair of springs 416. The springs 416 may bias the reticleholder 350 away from the closed end 344 of the second slot 340 which isproximate to the third side 314 of the housing 302.

A first push rod 420 may contact the cross slide 330 opposite thesprings 412. The first push rod 420 may contact a strike plate 422disposed in the cross slide 330. The strike plate 422 may prevent wearand tear on the cross slide 330 by an end of the first push rod 420.

The first push rod 420 may be adjustable relative to the housing 302.The first push rod 420 may position the cross slide 330 at a desiredposition in the first slot 322 by overcoming the bias of the springs412. The combination of the first push rod 420 and the springs 412 mayallow the cross slide 330 to be easily adjusted within the first slot322 and may also retain the cross slide 330 at its desired position inthe first slot 322. The first push rod 420 may be coupled to the azimuthadjusting screw 40 provided on the exterior 38 of the sight housing 30.

A second push rod 424 may contact the reticle holder 350 opposite thesprings 416. The second push rod 424 may contact an elongated strikeplate 426 disposed in the base 352 of the reticle holder 350. Theelongated strike plate 426 may prevent wear and tear on the base 352 ofthe reticle holder 350 by an end of the second push rod 424.

The second push rod 424 may be adjustable relative to the housing 302.The second push rod 424 may position the reticle holder 350 to a desiredposition in the second slot 340 by overcoming the bias of the springs416. The combination of the second push rod 424 and the springs 416 mayallow the reticle holder 350 to be easily adjusted within the secondslot 340 and may also retain the reticle holder 350 at its desiredposition in the second slot 340. The second push rod 424 may be coupledto the elevation adjusting screw 42 provided on the exterior 38 of thehousing 30.

Returning to FIG. 11, a protective window 430 may be sealed to thereticle 300 in accordance with one aspect of the present invention. Theprotective window 430 may shield the reticle 300 from dirt that hassettled within the sight 20. As previously described, the term “dirt”means soiling substances such as dust, oils and the like that arecapable of interfering with the user's view of the image at the reticle300.

The protective window 430 may disposed in the viewing aperture 354 ofthe reticle holder 350. The protective window 430 may be sealed in theviewing aperture 354 with a known adhesive for optical surfaces or thelike.

The protective window 430 shields a reticle 300 by collecting dirt at aplane 432 that is out of focus with the eye piece's 60 view of thereticle 300. Accordingly, the reticle 300 may be viewed and magnifiedwith little or no interference from dirt that has settled within thesight 20. The distance between the reticle 300 and the collecting plane432 may be varied by adjusting the position of the protective window 430in the viewing aperture 354 of the reticle holder 350.

As previously described, the image projected onto the reticle 300 may beviewed by the user through the eye piece 60. For the embodiment shown byFIG. 2, the eye piece 60 may magnify the image of the reticle 300. Inthis embodiment, the eye piece 60 may comprise a negative diverging lens440, a positive diverging lens 442 and a positive converging lens 444.The lenses may be adjusted relative to one another by a zoom ring 446mounted on an exterior of the eye piece 60. It will be understood thatadditional or disparate lenses may be used for the eye piece 60.

Returning now to the first mirror assembly 64, when the mirror 100 is inthe day position 104, the image of the scene 52 may be directed into theday channel 56. In the embodiment shown by FIG. 2, the day channel 56may include a 90 degree prism 450 to direct the image beam to the thirdoptical axis 255. A first lens set 452 and a second lens set 454 may bedisposed in the day channel 56 along the third optical axis 255. Analignment element 456 may be disposed along the third optical axis 255between the first lens set 452 and the second lens set 454.

The first lens set 452 may include a negative converging lens 460, apositive diverging lens 462 and a collimating lens 464. The second lensset 454 may include a collimating lens 466. The collimating lenses 462and 466 may collimate the image beam as it travels through the alignmentelement 456.

The lenses of the first and second lens sets 452 and 454 may be securedin a lens assembly as described above in connection with FIG. 7. Thelens assemblies for the first and second lens sets 452 and 454 may beclamped in a direction perpendicular to the third optical axis 255 asdescribed above in connection with FIG. 8.

In accordance with one aspect of the present invention, the alignmentelement 456 may deviate the image of the day channel 56 into alignmentwith the intensified image of the night channel 54 at the reticle 300.The alignment element 456 may be a Risley prism. Accordingly, the usermay switch the sight 20 between the night channel 54 and the day channel56 without need of realigning the reticle 300. It will be understoodthat the alignment element 456 may be used instead in the night channel54 to deviate the intensified image into alignment with the image of theday channel 56 at the reticle 300.

As shown by FIG. 13, the alignment element 456 may comprise a housing470 having a central aperture 472. A first annular frame 474 and asecond annular frame 476 may be disposed in the central aperture 472 ofthe alignment element 456. The first annular frame 474 and the secondannular frame 476 may rotate independently of one another and of thehousing 470.

In one embodiment, the first annular frame 474 may include a circularrecess 478 along an outside surface for receiving a circular lip 480 ofthe housing 470. The first annular frame 474 may rotate about thecircular lip 480 of the housing 470. An inside surface 482 of the firstannular frame 474 may abut an inside surface 484 of the second annularframe 476. The second annular frame 476 may be secured in the housing470 by a retainer 486. The outside surface of the second annular frame476 may include a circular recess 488 for receiving a lip 490 of theretainer 486. The second annular frame 476 may rotate about the circularlip 490 of the retainer 486. The retainer 486 may be threaded to engagea threaded section 491 of the housing 470.

The first annular frame 474 may include a first prism 492. The secondannular frame 476 may include the second prism 494. In one embodiment,the first prism 492 may have a flat back 496 and an angled face 498. Thesecond prism 494 may have a flat back 500 and an angled face 502.Preferably, the flat backs 496 and 500 of the first and second prisms492 and 494 face one another. Accordingly, the prisms 492 and 494 mayrotate in substantially parallel planes. This may allow the first andsecond prisms 492 and 494 to be placed in closely together withoutinterfering with one another during rotation.

As shown best by FIG. 14, the first prism 492 and the second prism 494may be of the same power. In this embodiment, the first and secondprisms 492 and 494 may have a combined power of zero when rotatedopposite one another and a power of twice that of either one whenrotated parallel with one another. Rotation of one prism relative to theother will deviate the image along a straight line at the reticle 300.Rotation of the prisms together will rotate the image at the reticle300. Accordingly, the image of the day channel 56 may be deviated to anypoint on the reticle by rotating the prisms 492 and 494 in concert,individually, or in some combination.

The power of the prisms 492 and 494 may be varied depending on thedesign and configuration of the sight 20. Prisms 492 and 494 of agreater power will allow greater deflection of the image beam at thereticle 300. Prisms 492 and 494 of a lesser power will allow greateraccuracy in deflecting the image beam at the reticle 300.

As shown best by FIG. 15, an adjustment device 506 for rotating thefirst annular frame 474 may comprise a threaded screw 508 for engaging aplurality of teeth 510 formed on a periphery 512 of the first annularframe 474. The threaded screw 508 may include an enlarged head 514 at atop end and an fixed nut 516 at an opposed end. The threaded screw 508may be positioned in operative relation with the teeth 510 of the firstannular frame 474 by recesses 518 and 520 formed in the housing 470.Accordingly, rotation of the threaded screw 508 may rotate the firstannular frame 474, and thus the first prism 492.

A clamping assembly 530 may be provided for fixably securing the firstannular frame 474 after the image has been aligned at the reticle 300.In one embodiment, the clamping assembly 530 may comprise a brace 532and a screw 534. The brace 532 may include a surface 536 adapted toengage the periphery 512 of the first annular frame 474. For theembodiment of FIG. 15, the surface 536 may have a concave shape adaptedto fit substantially flush against the teeth 510 of the periphery 512.

The screw 534 may engage a threaded section of the frame 470 and contactthe brace 532 opposite the surface 536. The screw 534 may be adjustablein the direction of the first annular frame 474 to secure the brace 532against the first annular frame 474.

Although not shown by FIG. 15, it will be understood that the secondannular frame 476 may include an adjustment device for rotating thesecond annular frame 476 as described above in connection with the firstannular frame 474. Additionally, a clamping assembly may be provided forsecuring the second annular frame 476 as described above in connectionwith the first annular frame 474.

In accordance with one aspect of the present invention, the sight 20 maybe mounted to the weapon 22 with non-integral members. The non-integralmembers allow the sight 20 to be designed independently of the weapon22. Accordingly, the sight 20 may be of a modular design that can bemounted to a weapon 22 with non-integral members configured for thatweapon.

FIG. 16 illustrates one embodiment of a mounting assembly 550 formounting the sight 20 to the weapon 22. As shown by FIG. 16, themounting assembly 550 may comprise a first foot 552 operativelyassociated with a first clamp 554 and a second foot 556 operativelyassociated with a second clamp 558. As described in more detail below,the feet 552 and 556 may be permanently secured to a bottom 560 of thesight 20 and may engage a rail 562 of the weapon 22 with the aid of theclamps 554 and 558. It will be understood that the clamps may bereversed within the scope of the invention.

The first foot 552 may include a top 563 adapted to engage a firstmounting section 564 of the bottom 560 of the sight 20. A tab 566 mayextend across the top 563 of the first foot 552 in a directionsubstantially parallel to the rail 562. A recess 568 may be formed inthe first mounting section 564 to receive the tab 566.

A side 570 of the first foot 552 may be adapted to engage a first edge572 of the rail 562. An opposite side 574 of the first foot 552 may beadapted to engage a second edge 576 of the rail 562 in combination withthe first clamp 554. The first clamp 554 may be coupled to the oppositeside 574 of the first foot 552 by a locking screw 580 and a nut 582. Thelocking screw 580 may be press fit into an aperture 584 formed in theside 570 the first foot 552 and extend from the opposite side 574 of thefirst foot 552. The projecting portion of the locking screw 580 may bethreaded to receive the nut 582.

The second foot 556 may include a top 586 adapted to engage a secondmounting section 588 of the bottom 560 of the sight 20. A tab 590 mayextend across the top 586 of the second foot 556 in a directionsubstantially normal to the rail 562. A recess 592 may be formed in thesecond mounting section 588 to receive the tab 590.

A side 594 of the second foot 556 may be adapted to engage the firstedge 572 of the rail 562. An opposite side 596 of the second foot 556may be adapted to engage the second edge 576 of the rail 562 incombination with the second clamp 558. The second clamp 558 may becoupled to the opposite side 596 of the second foot 556 by a lockingscrew 598 and a nut 600. The locking screw 598 may be press fit into anaperture 602 formed in the side 594 the second foot 556 and extend fromthe opposite side 596 of the second foot 556. The projecting portion ofthe locking screw 598 may be threaded to receive the nut 600.

The locking screw 598 may include a brace 604 for engagement with arecoil groove 606 of the rail 562. The brace 604 may prevent the sight20 from sliding along the rail 562 in response to the recoil of theweapon 22. In one embodiment, the brace 604 may be formed from a portionof the locking screw 598.

The rail 562 may be a Weaver rail as shown by FIG. 16. It will beunderstood that feet 552 and 556 and the clamps 554 and 558 may beconfigured to engage other types of rails 562 in accordance with theinvention.

The first foot 552 may be initially coupled to the first mountingsection 564 of the sight by a screw 608. Similarly, the second foot 556may be initially coupled to the second mounting section 588 of the sight20 by screws 610. It will be understood that pins and coupling devicesmay be used in the place of the screws 608 and 610.

Preferably, the screws 608 and 610 are slightly loose when the feet 552and 556 are initially coupled to the sight 20. This allows the sight 20to move slightly when engaged to the rail 562. The engagement of the tab566 with the recess 568 allows the forward portion of the sight 20 tomove parallel to the rail 562. The engagement of the tab 590 with therecess 592 allows the rearward portion of the sight 20 to move normal tothe rail 562. This movement prevents the sight 20 from twisting orbinding when the feet and clamps are secured to the rail 562, which maycause the night and day channels 54 and 56 to become unaligned.

After the feet and clamps feet are secured to the rail 562, the feet maybe permanently secured to the bottom 560 of the sight 20. In oneembodiment, the feet may be permanently secured with an adhesive and bytightening the screws 608 and 610. It will be understood that the feetmay be otherwise permanently secured to the sight 20.

The optical bench, housings, and frames of the sight 20 may be made ofaluminum. Aluminum may be preferred because it is lightweight andrelatively inexpensive. Additionally, aluminum is easy to machine andfinish. It will be understood that the optical bench, housings, andframes may be made from other types of materials that are strong andlightweight.

The lenses, windows, prisms and other optical components of the sight 20may be made of BK7 glass which is relatively inexpensive and well knownin the art. It will be understood that the optical components may bemade from other types of glass or polymers operable to transmit theimage of the scene 52. Preferably, the individual components include ananti-reflection coating to prevent reflections from interfering with theimage displayed on the reticle assembly 58.

Although the present invention has been described with severalembodiments, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present invention encompasssuch changes and modifications as fall within the scope of the appendedclaims.

What is claimed is:
 1. A scope, comprising: an image intensifier tubeincluding a projecting end operable to project an intensified image of ascene to a reticle disposed at an image plane; a protective,substantially non-lensing window disposed between the projecting end ofthe image intensifier tube and the reticle disposed at the image plane;the protective window sealed to the projecting end to obstruct dirt fromcontacting the projecting end; an eyepiece operable to view the imageplane; and the eyepiece operable to project a magnification of theintensified image.
 2. The scope of claim 1, wherein the protectivewindow is disposed adjacent to the projecting end.
 3. The scope of claim1, wherein the eyepiece is operable to magnify the intensified image. 4.The scope of claim 1, further comprising: at least one lens disposedbetween the projecting end and the image plane; and the lens operable tomagnify the intensified image.